Cyclic phospazene compounds and use thereof as additives of perfluoropolyether oils

ABSTRACT

Cyclic phosphazene compounds of formula (I):  
                 
wherein: 
 
Q is a cyclic compound of formula:  
                 
     A is an end group of the —OCF 2 X, —OC 2 F 4 X, —OC 3 F 6 X type, wherein X=F, Cl, H;    R f  and R′ f  are (per)fluoropolyoxyalkylene chains having a number average molecular weight in the range 280-5,000.

The present invention relates to anti-wear additives for lubricatingoils and greases.

More specifically the invention relates to additives having improvedanti-wear properties combined with improved solubility inperfluoropolyether oils, to the process for their preparation and tocompositions of oils or greases, preferably having a perfluoropolyetherstructure comprising said additives.

It is known that lubricants are largely used in systems containingmoving mechanical parts, and in contact with each other, mainly toreduce the wear of said mechanical parts. Said lubricants to have goodanti-wear properties in the time must be formulated with additives. Saidadditives must be soluble in the lubricant to guarantee the constancyand the uniformity of their anti-wear performances.

It is also known in the prior art that perfluoropolyethers have a verygood chemical, thermal and oxidative stability such to allow the usethereof as oils, greases or hydraulic fluids in many applications wherehydrogenated or silicone based oils or greases are not suitable. Amongsaid lubricants having a perfluoropolyether structure available on themarket, FOMBLIN® sold by Ausimont S.p.A. can be mentioned.

The anti-wear properties of the perfluoropolyether lubricants and thoseof the mineral oils do not satisfy the antiwear properties required inmany applications. Therefore said lubricants require the use ofanti-wear additives.

The anti-wear additives used in conventional lubricants, such forexample mineral or silicone oils, are not suitable to be used inperfluorinated lubricants due to their insolubility in the latter.

In U.S. Pat. No. 5,124,058 perfluoropolyether oils containing antiwearadditives are described, having the following perfluoropolyetherstructure of general formula.

TO (CF₂O)_(m)(CF₂CF₂O)_(n)(CF₂CF (CF₃)O)_(s)(CF (CF₃)O)_(p)T′

wherein:

-   T,T′ are equal or different from each other and selected from —CF₂X,    —C₂F₄X, —C₃F₆X with X=F, Cl or fluorinated end groups containing    reactive groups as carboxyls, ketones, amides, amines, alkoxyls,    with the proviso that at least one of the two end groups contains    one of said reactive groups; m, n, s, p are integers such that the    average molecular weight is in the range 1,000-100,000. The additive    concentrations in the perfluoropolyether lubricant are comprised    between 0.5% and 10%. However to obtain wear values of 0.56 mm,    determined by the ASTM D 4172B method, additive concentrations    higher than or equal to 3% by weight must be used. For example if a    Fomblin® perfluoropolyether oil having viscosity equal to 1,850 cSt    at 20° C. is used, to obtain a 50% wear decrease, 5% amounts of said    additive must be used.

The need was therefore felt to have available additives usable at lowerconcentrations, and giving improved anti-wear properties, compared withthe antiwear products of the prior art.

The Applicant has surprisingly and unexpectedly found additives capableto satisfy the above combination of properties.

An object of the present invention are cyclic phosphazene compounds ofgeneral formula (I):

wherein:

-   Q is a cyclic phosphazene structure (—N═P—)_(n′) wherein n′ is an    integer equal to 3 or 4, ω=0 or 1, preferably 0, ε=4 or 6, γ=0 or 1,    α and β are integers from 0 to 8, δ=0 or 1, with the proviso that:    -   when n′=3 and γ=1 then ε=4, α and β are integers from 0 to 5,        such that (α+β) is equal to 5; δ=1;    -   when n′=3 and γ=0 then ε=4, α and β are integers from 0 to 6,        such that (α+β) is equal to 6, ω and δ are equal to 0;    -   when n′=4 and γ=1 then ε is equal to 6, α and β are integers        from 0 to 7, such that (α+β) must be equal to 7 and δ=1;    -   when n′=4 and γ=0 then ε is equal to 6, α and β are integers        from 0 to 8, such that (α+β) must be equal to 8, ω and δ are        equal to 0;-   A is an end group of the —OCF₂X, —OC₂F₄X, —OC₃F₆X type, wherein X═F,    Cl, H;-   R_(f) and R′_(f) are (per)fluoropolyoxyalkylene chains having a    number average molecular weight in the range 280-5,000, preferably    500-2,000 and comprising one or more repeating units statistically    distributed along the chain selected from (C₃F₆O); (CFYO) wherein Y    is F or CF₃; (C₂F₄O); (CF₂ (CF₂). CF₂O) wherein x′ is an integer    equal to 1 or 2; (CR₄R₅CF₂CF₂O) wherein R₄ and R₅ are equal to or    different the one from the other and selected between H, Cl and    wherein one fluorine atom of the perfluoromethylene unit can    optionally be substituted with H, Cl or (per)fluoroalkyl, preferably    having from 1 to 4 carbon atoms.

The invention phosphazenes satisfy the following test: they arecompletely soluble, up to at least concentrations of 10% by weight, inFOMBLIN® Y25 perfluoropolyether oil having viscosity 250 cSt at 200C anda structureB—O-[CF(CF₃)CF₂O]_(m′)(CFXO)_(n′)-B′wherein:

-   B=B′=C₃F₇ and X=CF₃; m′ and n′ are integers such that the viscosity    has the above value.

With solubility of the invention compound in FOMBLIN® Y25 it is meantthat the mixture is clear and there is no opalescence, turbidity orphase separation after mixture stirring.

In particular the preferred compounds according to the invention are thefollowing:

wherein:

-   n′ is an integer equal to 3 or 4;-   A is an end group of the —OCF₂X, —OC₂F₄X, —OC₃F₆X type, wherein-   X=F, Cl, H;-   ω is an integer equal to 0 or 1, preferably 0;-   α and β are integers comprised between 0 and 5, such that α+β must    be equal to 5;-   R_(f) and R′_(f) are as above.

The preferred R_(f) are the following perfluoropolyoxy-alkylene unitsstatistically distributed along the chain:

-   (a) —CF₂—O-(CF₂CF₂O)_(p′)(CF₂O)_(q′)-CF₂—    -   wherein:    -   p′ and q′ are numbers such that the q′/p′ ratio is comprised        between 0.2 and 2 and the number average molecular weight is in        the above range;-   (b) —CFY—O-(CF₂CF(CF₃)O)_(r′)-(CF₂CF₂O)_(s′)-(CFYO)_(t′)-CFY—    -   wherein:    -   Y is as above; r′, s′ and t′ are numbers such that r′+s′ is in        the range 1-50, the t′/(r′+s′) ratio is comprised between 0.01        and 0.05, and the molecular weight is in the above range;-   (c) —CF    (CF₃)_(t′)(OCFY)_(t′)(OC₃F₆)_(u′)-OR″_(f)O—(C₃F₆O)_(u′)(CFYO)_(t′)CF(CF₃)-    -   wherein:    -   R″ f is a C₁-C₈ perfluoroalkylene; u′+t′ is a number such that        the number average molecular weight is in the above range; t′        can have also the value of zero; Y is as above;-   (d) —CF₂CF₂O-(CF₂(CF₂)_(x′)CF₂O)-CF₂CF₂—    -   wherein:    -   v′ is a number such that the molecular weight is in the above        range and x′ is 1 or 2;-   (e) —CF₃CH₂-(OCF₂CF₂CH₂)-OR″_(f)O-(CH₂CF₂CF₂O)_(w′)-CH₂CF₂—    -   wherein:    -   R″ f is as above; w′ is a number such that the number average        molecular weight is in the above range.

The preferred R′f are the following perfluoropolyoxy-alkylene unitsstatistically distributed along the chain:

-   (a′) -(CF₆O)_(q)(CFYO)_(r)-    -   wherein Y is —F, —CF₃; q and r are integers, the q/r ratio is        ≧2;-   (b′) -(C₃F₆O)_(q)-    -   wherein q is an integer, wherein the number average molecular        weight is that above;-   (c′) —(C₃F₆O)_(q)(C₂F₄O)_(t)(CFYO)_(r)    -   wherein Y is —F, —CF₃; q, t and r are integers such that the        number average molecular weight is that above.

The preferred formula (II) phosphazenes are those having n′=3, i.e. ofgeneral formula (IIA)

wherein R′_(f) has structure (a′) and a number average molecular weightbetween 500 and 700, Y=CF₃ and A=—OC₃F₆Cl.

Also formula (IIB) compounds can be used, wherein the phosphazene ringhas 4 —N═P— groups.

The preferred formula (III) phosphazenes are those with ω and α equal to0 having general formula (IIIA):

wherein R′_(f) has structure (a′) and number average molecular weight inthe range 500-700, Y=CF₃ and A=—OC₃F₆Cl; R_(f) has structure (a) and anumber average molecular weight in the range 1,000-2,000.

The Applicant has surprisingly and unexpectedly found that the inventioncompounds can be used as additives of perfluorinated lubricants, suchfor example perfluoropolyether based oils or greases, giving anti-wearperformances higher than those obtained with known additives, such forexample those described in U.S. Pat. No. 5,124,058, in terms of absolutewear values and the used lower concentrations. Besides, the inventioncompounds are soluble in perfluoropolyether oils as above defined.

The phosphazenes object of the invention are viscous, transparent andodourless liquids.

A further object of the present invention are compositions havinglubricating anti-wear properties comprising:

-   -   an oil or a grease having a perfluoropolyether structure;    -   from 0.05 to 10% by weight, preferably from 0.4 to 5% by weight,        of one or more phosphazenes of the present invention.

The phosphazenes, at the above concentrations, are, as said, completelysoluble in the lubricants having a perfluoropolyoxyalkylene structure,and the composition maintains unchanged the high oil or grease thermaland chemical stability. The perfluoropolyethers usable in the oil andgrease preparation are available on the market such for exampleFOMBLIN®, Krytox®, Demnum®.

As examples of perfluoropolyether oils the following classes can bementioned:

-   (1) B—O-[CF(CF₃)CF₂O]_(m′)(CFXO)_(n′)-B′    -   wherein    -   X is equal to —F or —CF₃;    -   B and B′, equal to or differnt from each other, are selected        from —CF₃, —C₂F₅ or —C₃F₇;    -   m′ and n′ are integers such that the m′/n′ ratio is comprised        between 20 and 1,000 and the product viscosity is between 10 and        4,000 cSt; the various units are statistically distributed along        the chain.    -    Said products can be obtained by photooxidation of the        perfluoro propene as described in GB 1,104,432, and by        subsequent conversion of the end groups as described in GB        1,226,566.-   (2) C₃F₇O-[CF(CF₃)CF₂O]_(o′)-D    -   wherein    -   D is equal to —C₂F₅ or —C₃F₇;    -   o′ is an integer such that the product viscosity is in the above        range.    -    Said products can be prepared by ionic perfluoropropylenoxide        oligomerization and subsequent treatment with fluorine as        described in U.S. Pat. No. 3,242,218.-   (3) {C₃F₇O-[CF(CF₃)CF₂O]_(p′)-CF(CF₃)-}₂    -   wherein    -   p′ is an integer such that the product viscosity is in the above        range.    -    Said products can be obtained by ionic telomerization of the        perfluoropropylenoxide and subsequent photochemical dimerization        as reported in U.S. Pat. No. 3,214,478.-   (4) B—O—[CF(CF₃)CF₂O]_(q′)(C₂F₄O)_(r′)(CFX)_(s′)-B′    -   wherein    -   X is equal to —F or —CF₃;    -   B and B′, equal to or different from each other, are selected        from —CF₃, —C₂F, or —C₃F₇;    -   q′, r′ and s′ are integers, the 0 also comprised, such that the        product viscosity is in the above range.    -    Said products are obtainable by photooxidation of a mixture of        C₃F₆ and C₂F₄ and subsequent treatment with fluorine as        described in U.S. Pat. No. 3,665,041.-   (5) B—O-(C₂F₄O)_(t′)(CF₂O)_(u′)-B′    -   wherein    -   B and B′, equal to or different from each other, are selected        from —CF₃, —C₂F₅ or —C₃F₇;    -   t′ and u′ are integers such that the t′/u′ ratio is comprised        between 0.1 and 5 and the product viscosity is in the above        range.    -    Said products are obtained by photooxidation of C₂F₄ as        reported in U.S. Pat. No. 3,715,378 and subsequent treatment        with fluorine as described in U.S. Pat. No. 3,665,041.-   (6) B—O-(CF₂CF₂CF₂O)_(v′)-B′    -   wherein

B and B′, equal to or different from each other, are selected from —CF₃,—C₂F, or —C₃F₇;

-   -   v′ is an integer such that the product viscosity is in the above        range.    -    Said products are obtained as reported in EP 148,482.

-   (7) D-O-(CF₂CF₂O)_(z′)-D′    -   wherein    -   D and D′, equal to or different from each other, are selected        from —C₂F₅, or —C₃F₇;    -   z, is an integer such that the product viscosity is in the above        range.    -    Said products can be obtained as reported in USP 4,52-3,039.

-   (8) R′″_(t)-[C(CF₃)₂-O—C(R″_(f))₂C(R″_(f))₂-O])_(w′)-R′″_(f)    -   wherein    -   R′″_(f) is a perfluoroalkyl group;    -   R″_(f) is equal to —F or perfluoroalkyl;    -   w′ represents a number higher than or equal to 8.    -    Said products can be obtained as reported in patent application        WO 87/00,538.

The preferred perfluoropolyether oils are those of the classes (1), (2),(4), (5) and (6). The perfluoropolyethers of the above classes from (1)to (8), have perfluoroalkyl end groups, are liquid with a very lowvapour tension value and have a viscosity, at 20° C., generallycomprised between 50 and 100,000 cSt, preferably between 100 and 2,000cSt.

The invention formulations can also contain other additives commonlyused in formulations of perfluoropolyether lubricants such as forexample anti-rust or antioxidant additives.

A further object of the present invention is a process to prepare theinvention phosphazenes by reaction, in the presence of a base, of aperchlorophosphazene of formula (IV) or (V):

with a fluorinated alcohol of formula AR′_(f)CF₂CH₂OH or optionally inadmixture with an alcohol of formula HOCH₂R_(f)CH₂OH, wherein A andR_(f), R′_(f) have the above meaning.

More specifically the process to obtain the phosphazenes of theinvention comprises the following steps:

-   -   (A) Condensation reaction between a fluorinated alcohol of        formula AR′_(f)CF₂CH₂OH, or a mixture thereof with an alcohol of        formula HOCH₂R_(f)CH₂OH, with the perchloro phosphazene of        formula (IV) or (V), in an equivalent ratio alcohol/phosphazenes        1:1. Said reaction is carried out in one step, in an organic        solvent, in the presence of a base and of a phase transfer        agent, at a temperature in the range 20° C.-100° C., preferably        40° C.-80° C. The organic solvent is selected from the known        fluorinated or hydrofluorinated solvents of the prior art and        having a boiling point in the range 20° C.-150° C, preferably        40° C-100° C., maintaining a ratio by weight solvent/fluorinated        alcohol in the range 0.5-10, preferably 2-5. As a base it is        used an aqueous solution of NaOH or KOH at a concen-tration        comprised between 20% and 60% w/w, preferably between 30% and        50% w/w, in amounts to have a KOH or NaOH excess comprised        between 2 and 10 times the fluorinated alcohol. The phase        transfer agent is preferably a phosphonium salt or a quaternary        ammonium salt known in the prior art, for example        tetrabutylammonium hydroxide, tetramethylammonium chloride, used        in a molar concentration comprised between 1% and 10% the        fluorinated alcohol. Depending on the temperature there are        reaction times generally comprised between 8 and 24 hours. At        the reaction end the phases are allowed to separate and the        heavy organic phase is recovered.    -   (B) The heavy organic phase obtained in step (A) is repeatedly        washed with water to remove the phase transfer agent and the        inorganic salts generated during the reaction. The obtained        product is then separated from the solvent by known methods, for        example by evaporation. The phosphazenes have been isolated with        a yield higher than 90%.

When in step A) both monofunctional AR′_(f)CF₂CH₂OH and bifunctionalHOCH₂R_(f)CH₂OH fluorinated alcohols are used, they are preferablyadded, separately, to the perchloro phosphazene, in more steps, in thefollowing order: first the monofunctional alcohol is added to convertthe 50% of the phosphazene chlorine atoms, then the bifunctional alcoholis added to let react on an average no more than one chlorine atom forphosphazene ring, lastly the remaining chlorine atoms are let completelyreact with a further addition of the monofunctional alcohol.

The present invention will be better illustrated by the followingExamples, which have a merely illustrative but not limitative purpose ofthe invention.

EXAMPLES Preparation of the Compounds Example 1 Preparation of theFormula (IIA) Compound Wherein A=a Molar Mixture 60/40 ofClCF₂—CF(CF₃)-O— and CF₃—CFCl—CF₂—O— and R′_(f)=(CF(CF₃)-CF₂—O—)_(m)with m=1-4 Such That AR′_(f)CF₂CH₂O— has a Number Average MolecularWeight Equal to 593

150 g (0.252 eq) of AR′_(f)CF₂CH₂OH (MW=594) of above defined formula,4.9 g of an aqueous solution at 40% by weight of Et₄N⁺OH⁻, 380 g of amixture of perfluorobutyl-tetrahydrofuran and perfluoropropyltetrahydropyran as solvent, 14.6 g (0.042 moles) ofhexachlorocyclotriphosphazene and 235 g of an aqueous solution of KOH at30% by weight are introduced in a 1 litre glass reactor equipped withmechanical stirrer, thermometer and a reflux condenser. The reactionmixture is heated at 60° C. and kept under stirring for about 15 hours.After cooling the phases are allowed to separate and the heavy organicphase is separated and washed with 150 g of water. The organic phase isseparated again and washed a second time with 150 g of an aqueous HClsolution at 2% by weight. After the organic phase separation the solventis distilled and the product stripped at 150° C. at a residual pressureof 10⁻² mbar for about 4 hours. 144 g of product are thus obtained witha yield equal to 93%. The IR and NMR (³¹p, ¹H, ¹³C and ¹⁹F) analysesconfirm the structure of the above indicated product.

Example 2 Preparation of the General Formula (IIA) derivative whereinA=a 60/40 mixture of HCF₂—CF(CF₃)-O— and CF₃—CFH—CF₂—O— andR′_(f)=(CF(CF₃)—CF₂—O—)_(m) with m=1-4 Such That AR′_(f)CF₂CH₂O— has aNumber Average Molecular Weight Equal to 557

150 g (0.269 eq) of AR′_(f)CF₂CH₂OH (MW=558) of above defined formula,5.2 g of an aqueous solution at 40% by weight of Et₄N⁺OH⁻, 380 g of amixture of perfluorobutyl tetrahydrofuran and perfluoropropyltetrahydropyran as solvent, 15.7 g (0.045 moles) ofhexachlorocyclotriphosphazene and 250 g of an aqueous KOH solution at30% by weight are introduced in a 1 litre glass reactor equipped withmechanical stirrer, thermometer and a reflux condenser. The reactionmixture is heated at 60° C. and kept under stirring for about 15 hours.After cooling the phases are allowed to separate and the heavy organicphase is separated and washed with 150 g of water. The organic phase isseparated again and washed a second time with 150 g of an aqueous HClsolution at 2% by weight. After the organic phase separation the solventis distilled and the product stripped at 150° C. at a residual pressureof 10⁻² mbar for about 4 hours. 142 g of product are thus obtained witha yield equal to 90.7%. The IR and NMR (³¹p, ¹H, ¹³C and ¹⁹F) analysesconfirm the product structure.

Example 3 Preparation of the General Formula (IIA) Dervative WhereinA=—OCF₃, CF₃CF₂O—, CF₃CF₂CF₂O— and R′_(f)=-(CF(CF₃)CF₂O)_(o)-(CFXO)_(p)- Wherein X is Equal to —F or —CF₃; o and p are Numbers Suchthat the p/o Ratio is in the Range 0.01-0.5 and Such thatAR′_(f)CF₂CH₂O— has a Number Average Molecular Weight Equal to 729

150 g (0.205 eq) of AR′_(f)CF₂CH₂OH (MW=730) of the above definedformula, 4 g of an aqueous solution at 40% by weight of Et₄N⁺OH⁻, 380 gof a mixture of perfluorobutyltetrahydrofuran and perfluoropropyltetrahydropyran as solvent, 11.9 g (0.034 moles) ofhexachlorocyclotriphosphazene and 200 g of an aqueous KOH solution at30% by weight are introduced in a 1 litre glass reactor equipped withmechanical stirrer, thermometer and a reflux condenser. The reactionmixture is heated at 60° C. and kept under stirring for about 15 hours.After cooling the phases are allowed to separate and the heavy organicphase is separated and washed with 150 g of water. The organic phase isseparated again and washed a second time with 150 g of an aqueous HClsolution at 2% by weight. After the organic phase separation the solventis distilled and the product stripped at 150° C. at a residual pressureof 10⁻² mbar for about 4 hours. 146 g of product are thus obtained witha yield equal to 95%. The IR and NMR (³¹p, ¹H, ¹³C and ¹⁹F) analysesconfirm the product structure.

Example 4 Preparation of the Formula (IIIA) Derivative Wherein A=a 60/40mixture of ClCF₂—CF(CF₃)-O— and CF₃—CFC1—CF₂—O— andR′_(f)=-(CF(CF₃)-CF₂—O—)_(m) with m=1-4 Such that AR′_(f)CF₂CH₂O— has aNumber Average Molecular Weight Equal to 593 and —OCH₂R_(f)CH₂O—,wherein R_(f) has Repeating Units as Defined in (c) in the Text, has anAverage Molecular Weight of 487

127.8 g (0.215 moles) of AR′_(f)CF₂CH₂OH (MW=594) of the above definedformula, 10.27 g (0.021 moles) of HOCH₂R_(f)CH₂OH (MW=489), 4 g of anaqueous solution at 40% by weight of Et₄N+OH⁻, 380 g of a mixture ofperfluorobutyltetrahydrofuran and perfluoropropyl tetrahydropyran assolvent, 15 g (0.043 moles) of hexachlorocyclotriphosphazene and 200 gof an aqueous KOH solution at 30% by weight are introduced in a 1 litreglass reactor equipped with mechanical stirrer, thermometer and a refluxcondenser. The reaction mixture is heated at 60° C. and kept understirring for about 15 hours. After cooling the phases are allowed toseparate and the heavy organic phase is separated and washed with 150 gof water. The organic phase is separated again and washed a second timewith 150 g of an aqueous HCl solution at 2% by weight. After the organicphase separation the solvent is distilled and the product stripped at150° C. at a residual pressure of 10⁻² mbar for about 4 hours. 134 g ofproduct are thus obtained with a yield equal to 96%. The IR and NMR(³¹p, ¹H, ¹³C and ¹⁹F) analyses confirm the product structure.

Example 5 Preparation of the Formula (IIIA) Derivative Wherein A=a 60/40Mixture of ClCF₂—CF(CF₃)-O— and CF₃—CFCl—CF₂—O— andR′_(f)=(CF(CF₃)-CF₂—O—)_(m) with m=1-4 Such that AR′_(f)CF₂CH₂O has aNumber Average Molecular Weight Equal to 593 and —OCH₂R_(f)CH₂O-1Wherein R_(f) has Repeating Units as Defined in (a) in the Text, has anAverage Molecular Weight of 1437

127.8 g (0.215 moles) of AR′_(f)CF₂CH₂OH (MW=594) of the above definedformula, 30.9 g (0.021 moles) of HOCH₂R_(f)CH₂OH (MW 1439), 4 g of anaqueous solution at 40% by weight of Et₄N⁺OH⁻, 380 g of a mixture ofperfluorobutyltetrahydrofuran and perfluoropropyl tetrahydropyran assolvent, 15 g (0.043 moles) of hexachlorocyclotriphosphazene and 200 gof an aqueous KOH solution at 30% by weight are introduced in a 1 litreglass reactor equipped with mechanical stirrer, thermometer and a refluxcondenser. The reaction mixture is heated at 60° C. and kept understirring for about 15 hours. After cooling the phases are allowed toseparate and the heavy organic phase is separated and washed with 150 gof water. The organic phase is separated again and washed a second timewith 150 g of an aqueous HCl solution at 2% by weight. After the organicphase separation the solvent is distilled and the product stripped at150° C. at a residual pressure of 10⁻² mbar for about 4 hours. 158 g ofproduct are thus obtained with a yield equal to 96%. The IR and NMR(³¹p, ¹H, ¹³C and ¹⁹F) analyses confirm the product structure.

Application Tests

The phosphazenes of Examples 1-5 have been added to perfluoropolyetherlubricating oils and the so obtained compositions have been evaluated interms of anti-wear properties, as well those of the non additivedperfluoropolyether oils and those of the same additived oils accordingto U.S. Pat. No. 5,124,058. The anti-wear property determination hasbeen carried out by the ASTM D 4172 test.

Three AISI N. E-52100 steel spheres, having a diameter of 12.7 mm, 25 EP(Extra Polish) degree, previously cleaned by washing by immersion inn-hexane (15 min) and subsequently in Galden® HT55 (15′) cavity bydrying, are put in a vessel having a suitable cavity so as to have threepoints in contact and, then, they are covered with the lubricant to betested. A fourth sphere of the same kind, connected to an electricengine which allows its rotation, is placed on the three mentionedsoheres with a load of 40±0.2 kgf (392N). The whole is assembled, closedand heated to 75°±2° C. When said temperature has been reached, thefourth sphere, placed over the three of reference, is let rotate at therate of 1200±60 rpm for 60±1 minutes. At the end of the test the vesselis disassembled, the lubricant is removed and the wear of the threespheres contained therein is evaluated by optical microscopy having aprecision of 0.01 mm. The wear value expressed in mm, is obtained asarithmetic mean of six readings, measuring for each sphere, withoutremoving it from the cavity, the wear diameter in the rotation directionand the diameter perpendicular to the first diameter.

For the tests perfluoropolyether lubricating oils having differentviscosities have been used, having structureCF₃O(C₃F₆O)_(n)(CF₂O)_(m)CF₃ wherein n/m=20, commercially known asFomblin® Y.

Example 6

A mixture formed by 95% by weight of Fomblin® YR1800, having kinematicviscosity measured at 20° C. of 1850 cSt, and 5% by weight of astructure (IIA) compound (Example 3), has been subjected to the ASTM D4172 test according to the conditions described in the invention. Thewear value obtained as an average of six readings is 0.59 mm.

Example 7

The non additived Fomblin® YR1800 is subjected to the ASTM D 4172 testaccording to the conditions described in the invention. The wear valueobtained as an average of six readings is 1.5 mm.

Example 8

A mixture formed by 99% by weight of Fomblin® YR, having a kinematicviscosity measured at 20° C. of 1200 cSt, and 1% by weight of astructure (IIIA) compound (Example 5), has been subjected to the ASTM D4172 test according to the conditions described in the invention. Thewear value obtained as an average of six readings is 0.57 mm.

Example 9

Fomblin® YR, having kinematic viscosity measured at 20° C. of 1,200 cSt,has been subjected to the ASTM D 4172 test according to the conditionsdescribed in the invention. The wear value obtained as an average of sixreadings is 1.3 mm.

Example 10

A mixture formed by 97% by weight of Fomblin® Y45, having a kinematicviscosity measured at 20° C. of 450 cSt, and 3% by weight of a structure(IIIA) compound (Example 5), has been subjected to the ASTM D 4172 testaccording to the conditions described in the invention. The wear valueobtained as an average of six readings is 0.40 mm.

Example 11

Fomblin® Y45, having a kinematic viscosity measured at 20° C. of 450cSt, has been subjected to the ASTM D 4172 test according to theconditions described in the invention. The wear value obtained as anaverage of six readings is 1.0 mm.

Example 12

A mixture formed by 99.56 by weight of Fomblin® Y25, having a kinematicviscosity measured at 20° C. of 250 cSt, and 0.5% by weight of astructure (IIIA) compound (Example 5), has been subjected to the ASTM D4172 test according to the conditions described in the invention. Thewear value obtained as an average of six readings is 0.38 mm.

Example 13

A mixture formed by 99.5% by weight of Fomblin® Y25, having a kinematicviscosity measured at 20° C. of 250 cSt, and 0.5% by weight of astructure (IIA) compound (Example 1), has been subjected to the ASTM D4172 test according to the conditions described in the invention. Thewear value obtained as an average of six readings is 0.46 mm.

Example 14

A mixture formed by 99.5% by weight of Fomblin® Y25, having a kinematicviscosity measured at 20° C. of 250 cSt, and 0.5% by weight of astructure (IIA) compound (Example 2), has been subjected to the ASTM D4172 test according to the conditions described in the invention. Thewear value obtained as an average of six readings is 0.47 mm.

Example 15

Fomblin® Y25, having a kinematic viscosity measured at 20° C. of 250cSt, has been subjected to the ASTM D 4172 test according to theconditions described in the invention. The wear value obtained as anaverage of six readings is 0.83 mm.

Example 16

A mixture formed by 99.5% by weight of Fomblin® Y25, having a kinematicviscosity measured at 20° C. of 250 cSt, and 0.5% by weight of astructure (IIIA) compound (Example 4), has been subjected to the ASTM D4172 test according to the conditions described in the invention. Thewear value obtained as an average of six readings is 0.40 mm.

Example 17 (Comparative)

Example 6 has been repeated but by using as additive 5% by weight of anadditive reported in U.S. Pat. No. 5,124,058 (Example 1) having thefollowing structure:

CF₃O-(CF₂O)_(n)(CF₂CF(CF₃)O)_(s)(CF(CF₃)O)_(p)-T

wherein T=CF₂—C(OH)₂CF₃ (75%)CF₂—COOH (25%)

-   s/p=10; s/m=20; p/n=2,-   said additive indicated in Table 1 as DA 305.-   The wear value obtained as an average of six readings is 0.76 mm.

Example 18 (Comparative)

Example 8 has been repeated but by using as additive it of the additivedescribed in the Example 17 (comparative). The wear value obtained as anaverage of six readings is 0.75 mm.

Example 19 (Comparative)

Example 10 has been repeated but by using as additive 3% of the additivedescribed in the Example 17 (comparative). The wear value obtained as anaverage of six readings is 0.56 mm.

Example 20 (Comparative)

Example 12 has been repeated but by using as additive 1% of the additivedescribed in the Example 17 (comparative). The wear value obtained as anaverage of six readings is 0.80 mm. TABLE 1 % by Lubricant viscosityAdditive weight of Wear, cSt at 20° C. type additive mm  6 1850 IIA (Ex.3) 5 0.59  7 1850 — — 1.50  8 1200 IIIA (Ex. 5) 1 0.57  9 1200 — — 1.3010 450 IIIA (Ex. 5) 3 0.40 11 450 — — 1.00 12 250 IIIA (Ex. 5) 0.5 0.3813 250 IIA (Ex. 1) 0.5 0.46 14 250 IIA (Ex. 2) 0.5 0.47 15 250 — — 0.8316 250 IIIA (Ex. 4) 0.5 0.40 17 (comp) 1850 DA 305 5 0.76 18 (comp) 1200DA 305 1 0.75 19 (comp) 450 DA 305 3 0.56 20 (comp) 250 DA 305 1 0.80

1-7. (canceled)
 8. Compositions having lubricating anti-wear propertiescomprising: an oil or a grease having a perfluoropolyether structure;and from 0.05 to 10% by weight of a following phosphazene compound offormula (I) or (II) or (III) or (IIA) or (IIB) or (IIIA), or mixturesthereof: wherein formula (I) is:

wherein: Q is a cyclic phosphazene structure

wherein n′ is an integer equal to 3 or 4, ω=0 or ε=4 or 6, y=0 or 1, αand β are integers from 0 to
 8. δ=0 or 1, with the proviso that: whenn′=3 and y=1 then ε=4, α and β are integers from 0 to 5, such that (α+β)is equal to 5; δ=1; when n′=3 and y=1 then ε=4, α and β are integersfrom 0 to 6, such that (α+β) is equal to 6, ω and δ are equal to 0; whenn′=4 and y=1 then ε is equal to 6, α and β are integers from 0 to 7,such that (α+β) must be equal to 7 and δ=1; when n′=4 and y=0 then ε isequal to 6, α and β are integers from 0 to 8, such that (α+β) must beequal to 8, ω and δ are equal to 0; A is an end group of the —OCF₂X,—OC₂F₄X, —OC₃F₆X type, wherein X=F, Cl, H; R_(f) and R′_(f) are(per)fluoropolyoxyalkylene chains having a number average molecularweight in the range 280-5,000 and comprising one or more repeating unitsstatistically distributed along the chain selected from (C₃F₆O); (CFYO)wherein Y is F or CF₃; (CF₂F₂O); (CF₂)_(x′)CF₂O wherein x′ is an integerequal to 1 or 2; (CR₄R₅CF₂O) wherein R₄ and R₅ are equal to or differentthe one from the other and selected between H, Cl and wherein onefluorine atom of the perfluoromethylene unit can optionally besubstituted with H, Cl or (per)fluoroalkyl; R_(f) and R′_(f) are(per)fluoropolyoxyalkylene chains having a number average molecularweight in the range 280-5.000, preferably 500-2,000 and comprising oneor more repeating units statistically distributed along the chainselected from (C₃F₆O); wherein formulae (II) or (III) respectively are:

wherein: n′ is an integer equal to 3 or 4: A is an end group of the—OCF₂X, —OCF₂X, —OC₂F₄X, —OC₃F₆X type wherein X=F, Cl, H: ω is aninteger equal to 0 or 1; α and β are integers comprised between 0 and 5,such that α+β must be equal to 5; R_(f) and R′_(f) are as above whereinformula (IIA) is:

wherein R′_(f) has structure (a′) and a number average molecular weightbetween 500 and 700, Y=CF₃ and A=—OC₃F₆Cl wherein formula (IIB) is:

wherein R′_(f) is as above wherein formula (IIIA) is:

wherein R′_(f) has structure (a′) and number average molecular weightcomprised between 500 and 700, Y=—CF₃ and A=—OC₃F₆Cl; R_(f) hasstructure (a) and a number average molecular weight in the range1.000-2,000.
 9. Compositions according to claim 8, wherein theperfluoropolyether of the lubricating oil or grease is selected from thefollowing classes: (1) B—O-[CF(CF₃)CF₂O]_(m′)(CFXOQ)_(n′)-B′ wherein Xis equal to —F or —CF₃; B and B′, equal to or different from each other,are selected from —CF₃, —C₂F₅ or —C₃F₇; m′ and n′ are integers such thatthe m′/n′ ratio is in the range 20-1,000 and the product viscosity is inthe range 10-4,000 cSt; the various units are statistically distributedalong the chain; (2) C₃F₇O-[CF(CF₃)CF₂O]_(o′)-D wherein: D is equal to—C₂F, or —C₃F₇; o′ is an integer such that the product viscosity is inthe above range; (3) {C₃F₇O-[CF(CF₃)CF₂O]_(p′)-CF(CF₃)-}₂ wherein: p′ isan integer such that the product viscosity is in the above range; (4)B—O-[CF(CF₃)CF₂O]_(q′)(C₂F₄O)_(r′)(CFX)_(s′)-B′ wherein: X is equal to—F or —CF₃; B and B′, equal to or different from each other, areselected from —CF₃, —C₂F₅ or —C₃F₇; q′, r′ and s′ are integers, the 0also comprised, such that the product viscosity is in the above range;(5) B—O-(C₂F₄O)_(t′)(CF₂O)_(u′)-B′ wherein: B and B′, equal to ordifferent from each other, are selected from —CF₃, —C₂F₅ or —C₃F₇; q′,r′ and s′ are integers, the 0 also comprised, such that the productviscosity is in the above range; (5) B—O-(C₂F₄O)_(t′)(CF₂O)_(u′)-B′wherein: B and B′, equal to or different from each other, are selectedfrom —CF₃, —C₂F, or —C₃F₇; t′ and u′ are integers such that the t′/u′ratio is comprised between 0.1 and 5 and the product viscosity is in theabove range; (6) B—O-(CF₂CF₂CF₂O)_(v′)-B′ wherein: B and B′, equal to ordifferent from each other, are selected from —CF₃, —C₂F, or —C₃F₇; v′ isa number such that the product viscosity is in the above range; (7)D—O-(CF₂CF₂—O)_(z′)-D′ wherein: D and D′, equal to or different fromeach other, are selected from —C₂F₅ or —C₃F₇; z′ is an integer such thatthe product viscosity is in the above range; (8)R′″_(f′″)[C(CF₃)₂C(R′″_(f))₂C(R′″_(f))₂-O—]_(w′)R′″_(f) wherein: R′″_(f)is a perfluoroalkyl group; R″_(f) is equal to —F or perfluoroalkyl; w′represents a number higher than or equal to
 8. 10-14. (canceled) 15.Compositions according to claim 8, wherein the compositions comprisefrom 0.5 to 5% by weight of the phosphazene compound of formulae (I),(II), (III), (IIA), (IIB), (IIIA), or mixtures thereof.